How to troubleshoot slow network performance with Realtek 8169s?

Juha Saarinen juhasaarinen at gmail.com
Sun Jul 3 11:09:34 GMT 2005


On 7/3/05, Ted Mittelstaedt <tedm at toybox.placo.com> wrote:
> 
> The Realtek is a cheap adapter.  You can try hard-coding the
> media type to see what happens, but the fact remains this is
> nowhere near as good a card as the 82801B.  As a result of this
> there hasn't been that much attention to driver optimizations,
> you can review the work here:
> 
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/re/if_re.c
> 
> If playing around with the media type doesen't fix it you can
> try a send-pr but your best off just pulling the card and
> replacing it with another Intel, then mailing the card to one
> of the driver developers.  Maybe in 6 months to a year you
> might see a faster driver in FreeBSD - or maybe not.

Yeah, I know the 8169s isn't the flashest card in the universe and I
don't mind donating a card or two to the developers, but with further
testing -- assuming iperf isn't lying -- it seems the driver is OK and
there's something happening further up the chain that I don't
understand yet.

What's weird is that with both 100 and 1000Mbit/s connections, the max
speed is a quarter of the link speed when using applications such as
ftp for transferring files. With iperf, I see 92Mbit/s on 100Mbit/s
and 400-640Mbit/s on 1000mbit/s connections depending on the
direction.



-- 

Juha


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